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Topics - Hydron

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3
General Chat / MOVED: My drsstc
« on: September 15, 2020, 10:55:40 PM »
Moved to DRSSTC board

4
Note: I originally posted this a few years back on 4hv, but unfortunately attachments are broken on that forum and they're kinda necessary to view this properly, so I've reposted this here. "Recently" isn't really accurate anymore, and the Pearson family has grown to include a couple of baby SMA-connector model 2877 CTs. The dodgy BNC on the 7800 has also been fixed as described here: https://highvoltageforum.net/index.php?topic=435.0. I've also since had a play with some other ways of constructing DIY CTs that might be less susceptible to noise, but they haven't really been tested in anger yet - if I have any luck then I'll make a new topic.

I have recently acquired a trio of Pearson wide band current transformers/monitors, so I though that I'd do a bit of work investigating their behavior and that of a home-made DRSSTC CT (constructed for primary current measurement and ZCS bridge switching).

Pearsons:
- 7800, 3525 and 4100
- 0.01, 0.1 and 1V/A respectively into high-Z input, half that into 50R
- 2MHz, 15MHz and 35MHz high frequency 3dB point respectively
- All rated for <6deg phase shift at <10% of high 3dB freq
- Performance measurements on all 3 indicate that they meet datasheet specifications (tested to 10MHz)
- At frequencies >10% of high 3dB freq phase shift is strongly affected by position of wire in central hole
- If wire is well centered phase shift seems significantly lower than Pearson specifies



DIY DRSSTC CT:
- Cascaded CT wound on mystery ferrites, probably EMI suppression ones
- Bottom right holds the first winding, and this is where the wire with current to be measured passes through
- Top (blue) CTs are for bridge ZCS switching and OCD
- Bottom left CT is for measurement, and is terminated with 10R burden and 39R termination resistors inside the BNC
- CTs are ~1000:1 (I think 31:1 x 32:1) overall, giving 0.01V/A output on the BNC (into high-Z input, half that into 50R)



The first problem I ran into was the huge and heavy Pearson 3525 being too heavy to lug from the UK (where I bought it and now live) to NZ (where my DRSSTC lives).

This means that I only had the 7800 and 4100 to compare against the DIY CT, and the only one that can be trusted for low phase shift at frequencies over 200kHz is the 4100.

The 4100 at 1V/A isn't ideal for TC measurements even with a 20dB (10x) attenuator, as it's only rated for 500Apk/5Arms, so I had to get creative:
- At the end of this paper http://mdk2001.web.cern.ch/mdk2001/Proceedings/SessionPoster/Cordingley.pdf, linked in this thread: http://4hv.org/e107_plugins/forum/forum_viewtopic.php?175696 there is a suggestion of cascading a simple CT with a wide band CT for measuring high currents at high frequencies (while giving up low freq perfomance). I had a go at this with a 10:1 CT on a decent ferrite ring, seen below:


- I compared the 4100 cascaded with a 10:1 DIY CT against the 3525, giving the following result:

(sorry - I couldn't find the original of this so it's only the thumbnail left from 4hv!)

(Note the scales change between captures, and should be checked carefully - e.g. the phase shift above looks big but is under 10deg. Also note that the Pearson 4100 on it's own is only specified for <6deg phase shift between 1.4kHz and 3.5MHz, and the 3525 only up to 1.5MHz)

- This looks really good for frequencies >50kHz - almost as good as the same comparison without the cascaded 10:1 CT!

When I got to NZ I ran a couple of comparisons of the 4100 Pearson (with and without the 10:1 CT on it's input) against the 7800 using the primary circuit of my DRSSTC.

Comparing the 4100 (with 10:1 CT on input and 20dB atten) with the 7800 with the coil running at 850Apk shows no difference other than slightly lower gain on the 7800:


If the 4100 (without the 10:1 CT on the input, but with a 20dB attenuator) is directly compared with the 7800, it has significantly lower susceptibility to noise than the 7800, but it must be remembered that the signal at the CT output is 100x larger than that of the 7800, which is also possibly at a disadvantage being a clamp-on model:

(7800 red, 4100 blue)

Finally I compared the Pearson 4100 (with 10:1 input CT and 20dB attenuator = 0.01V/A) with the 0.01V/A DIY CT, first measuring gain/phase:

Looks rather good, easily usable to over 1MHz!
Seems the cascaded CT approach used for most DRSSTCs is actually a very good one, and not just because of the low number of windings needed vs a single stage 1000:1 CT

When tested in a DRSSTC, we see that the main advantage of the Pearson in this application is noise immunity (it's shielded, whereas the DIY CT is not). Bridge switching noise, especially on the first couple of transitions where ZCS isn't perfect, clearly shows up:

(Red is Pearson, blue is DIY CT)


In conclusion:

The cascaded home-wound approach of CT construction used for DRSSTCs seems to provide extremely good performance for the application. They are not as noise immune as the shielded wide-band commercial models, but this is mostly seen on the initial low-current transitions, seems to clear up as the bridge switches higher current (where accuracy is most needed anyway!). Low frequency performance is likely poor (and certainly won't get anywhere near the 5Hz of the 7800), but it irrelevant in this application.

It can also be seen that the cascaded CT approach can be used to allow a low-current wide-band CT to measure at least an order of magnitude higher current than otherwise possible, while maintaining good noise immunity. Again, this will be high-freq only, but still fine for DRSSTC use. This could be really handy if a 1V/A unit is available cheaply (mine was under 50 USD, albeit with the BNC in bad condition) and higher current capability or a larger center hole is needed.

Something that could be interesting for someone to try in the future is to attempt to shield a DIY CT in a similar manner as done for the commercial CTs (small gap in shield, sometimes even overlapped, to avoid a shorted turn). Might be a good way to get decent performance for TC measurements on a very low budget, without having to luck out on ebay!

5
I've just finished laying out a couple of boards for the bridge and gate drive of my larger 160mm DRSSTC which I'll be upgrading when I'm in NZ over the (southern) summer. These may be of interest to others, so I've uploaded all the design files to github, and also put a couple of 3d renders below:

https://github.com/Hydron-4hv/Big_DRSSTC_Bridge_PCBA

https://github.com/Hydron-4hv/Big_DRSSTC_Gate_Drive_PCBA


Notes:
- Github README has the majority of explanation in it
- The schematic pdfs have a 3d model in them, open with acrobat reader to view
- Original files are in Altium format, I may be able to export to something else if needed (KiCAD is unlikely though, sorry!)

I'd welcome any suggestions/criticism, these are going off to JLCPCB in the next few days and obviously I'd like them to be correct!

I may have some more PCBs coming up too, but they are likely to to be more specific to my design (though I will share them anyway).

6
Just a quick post to share a trick I found useful for replacing a BNC connector without rear access on a Model 4100 Pearson "Wideband Current Monitor" (internally terminated wideband CT).

These items are made with a brass case surrounding the CT core, and are 100% epoxy potted _after_ the BNC connector is screwed to the case and it's centre pin soldered to the CT output. They are then dipped in (green) paint. See below for an undamaged example:

Example of the type of BNC used:

The actual part number seems to be a UG-290A/U Amphenol RF 50R BNC, but there are equivalent (cheaper, non MIL-Spec) parts widely available with the same dimensions, including the B6551A1-NT3G-50 I used in my repair.

I obtained one of these CTs on ebay for a steal, but it came with a badly damaged (dented, deformed) BNC. While I was able to beat it back into enough shape to work with some BNC connectors, it was still a problem with most of my cables/connectors, so a solution was desirable.

Although the paint covering the base of the BNC can be removed to access the screws and free the base from the unit, the centre pin is still soldered to a wire trapped by epoxy, so the connector cannot be removed. Brute force could be tried to pull the connector off (leaving the pin behind) but risks breaking internal connections. Thankfully I found another way!

It turns out that it's possible to "remotely" de-solder the wire at the back of a BNC socket by heating up a conductive pin inserted into the front. I found a diode with thick copper legs that _just_ fit into the front socket, and cut one off to use. Heated with a soldering iron set to ~325C and placed just above where the copper pin entered the insulator inside the BNC, it managed to desolder the pin at the back and allow the BNC to be removed. This was probably helped by teflon's high temperature resistance (~350C melting) and the leaded solder used in the old CT, but can probably still be done for lead-free by using a higher temperature and accepting that the insulator may melt and make a mess (not a big issue as that part is being replaced anyway).

Behind the BNC was bare brass with tapped holes at the corners and a hole milled through for the central protrusion and connection (sorry forgot to take a pic of this). Epoxy potting compound had surrounded the space where the rear protrusion of the BNC had been, with the termination wire down a little hole formed by the removal of the central pin. After checking that the new BNC would fit (the rear insulator was thankfully the exact same diameter, and slightly shorter) I sanded down the pin at the back of the new BNC to match the (slightly shorter) pin of the old one, and also opened up the solder cup a bit.

At this point I had two options - do the de-solder trick in reverse to solder the connection again from the front with the new BNC (I tested this on a scrap BNC, and it worked without melting the insulator with a 325C iron and leaded solder), or remove the new BNC pin from the connector and fit it separately. With a teflon insulator the pin could be pressed out relatively easily (it's not actually meant to be removed!), and as the bottom of the hole with the CT termination wire was full of epoxy (i.e. strong enough to withstand the BNC connector being pushed back onto the central pin), I decided to solder the pin on first, then push the BNC back onto it. This step was fairly easy - I was just careful that the pin was straight and at the right height, and got a fine tipped iron into the base to hit both the end of the termination wire and the solder cup for a nice solid joint. The BNC shell was aligned to match the screw holes and pressed onto the pin (alignment is critical, as twisting or pulling after the fact to line things up is risky!). Finished result along with the old bent BNC is shown below - good as new:


...uh, I take back the description of "quick post", but hopefully this trick can help others with a similar problem!

7
As part of the design process for my (under construction) QCW coil I took a long look at the different TO-247 (and similar) IGBTs available, and ended up deciding to buy some FGA60N65SMD parts from Mouser, with FGY75N60SMDs coming in as a second choice, mainly due to significantly increased cost. The criteria and pros/cons I used to decide this are quoted below from one of my 4hv posts (see http://4hv.org/e107_plugins/forum/forum_viewtopic.php?180799.0#post_180879 for full thread context):

Quote
I have just ordered a bunch of FGA60N65SMDs myself after quite a lot of comparison and evaluation.

I had the following wish list when picking IGBTs:
- Reasonable Qg to make driving at 350kHz for 10-15ms at a time not too difficult
- Fast, with low Eoff (will be some hard switching - OFF only - in QCW)
- Cheap (am running multiple parallel bridges, so needed a few!)
- Low Rjc to keep die temperature swing down

After hours of searching I ended up back where I started - overall the standard choice of 60N65s(/60N60s) were the best option, and are well tested. Second pick was the FGY75N60SMD, with the following pros/cons compared to the 60N6x parts:

Cons:
- about 50% more expensive
- more Qg (though not excessive)
- slightly higher Eoff per amp, though significantly lower fall time, so a little dubious about how much difference there really is here
- no mounting hole for those who need this (am using clips so I don't care)
- no 650V rated option, only 600V (though I suspect the 600 vs 650 is mostly packaging related, and can likely be disregarded)

Pros:
- no mounting hole to reduce heatsink contact area
- lower Rjc thermal impedance, especially for the co-pack diode (which has less than half of the 60N65 value). Diode is only important if using freewheeling or phase shift QCW
- maybe easier to find?

I was very close to getting the 75N60s, mainly due to the thermal impedance stuff, as I plan to use the freewheeling diode quite a bit for phase shift QCW modulation. In the end the 60N65 seemed likely to be good enough, and if I have issues then there's still an upgrade path!

As a heads up, stock seems to be a bit scarce of some of these parts - Mouser had the best price on the 60N65s so I bought from them, but they only have 11 left now and a 1 YEAR lead time on more!

The Mouser stock of 11 mentioned is now completely gone, but as suggested by loneoceans, it's also worth checking the other more wholesale orientated distibutors like Arrow/AVNET too for this sort of thing (I would have saved about 10% had I done so).

This brings me to the Aliexpress part of the story - having ordered a bunch of legitimate 60N65s, I thought I'd look on Aliexpress to see if there were any suspiciously cheap 75N60s to buy as a second option :P

Playing Aliexpress roulette with the larger 75N60 parts vs 60N60/60N65s seemed to have a few pros/cons:

- Fewer sellers of the larger parts mean it's easier to sort through the options, but less choice of sellers/quantities/prices
- There aren't any really cheap "Power TO247" parts that could be relabeled for a counterfeit 75N60, compared to the much more common TO-247/TO-3P packages used by the 60N6x parts. Anything that actually has a real IGBT die inside should have a current rating at least as high as a 75N60, and there's probably not much to be gained by swapping something else for what is one of the smaller/cheaper Power-TO247 parts.

Sorting the options down to sellers that:
a) Had a picture of the real part, not something with the Fairchild "F" missing or just a completely different package
b) Offered singles or small lots (up to 10 parts) at a reasonable price & shipping rate
Gave 2-3 options of sellers to purchase from.

In the end I chose these: https://www.aliexpress.com/item/10PCS-FGY75N60SMD-600V75A/32327762387.html because the seller had much more of a history than the others, with many positive reviews to go with a few bad ones complaining of fakes etc (of different products, not the 75N60s). Price ended up being 1.75 USD each, or about 30% of what I would have paid from the normal sources (e.g. Mouser, RS etc) - cheap but not so insane that it MUST be fake. US large quantity prices (without ~20% EU sales tax) are much closer to what I paid than what I could get buying 10 in Europe.

The 10 parts I ordered (1 lot) shipped within a few days, with the post taking about 2 weeks. When they arrived I noted the following:
a) All 10 were just thrown in a single (non-antistatic) bag inside the padded postal envelope. Some legs had minor bends and the epoxy of the packages had a fair number of light scratches in it, possibly from shipping with no protection from the other parts in the bag.
b) The packages exactly matched datasheet information with the exception that the legs were longer than specified.
c) No evidence of any sanding/grinding of the package for re-marking. All expected tooling marks were present, including moulded numbers/letters in one of the recesses.
d) Laser engraving of part number exactly matched that of other Fairchild/ONsemi IGBTs I have, e.g. shape of letters, where the laser started/stopped (see pic)
e) Testing all 10 using a multi-meter showed expected behavior of an IGBT - 1 diode drop when measured backwards, open-circuit in forward direction until the gate is charged at which point they showed approx. 1 diode drop in that direction too.

So far so good!

For thoroughness I wanted to do a couple of extra tests. The first was to sacrifice a part to mechanically decap and check that die size was realistic. I was very happy to find that searching for "FGY75N60SMD die size" gives the bare die datasheet: https://shop.micross.com/pdf/fairchild/igbt/FGY75N60SM_IGBT_DIE.pdf as the first result; exactly what I needed to comprehensibly confirm that the parts I'd ordered were real, or at least QC rejects, rather than a completely different part. Grinding down the package revealed a large IGBT die of the exact dimensions given in the bare die datasheet, along with a smaller diode die. The diode die was much thicker than the IGBT, which also meets the expectations of a "Field Stop" IGBT die, which is significantly thinner than the original wafer (75 microns in this case).

I also used a "Megger" to test the parts for OFF-state leakage at up to 650V, getting much less than the datasheet value of 250uA (cannot remember exact value, but may have been in the single digit uA).

Finally I put them in a half bridge and ran them up to ~150A peak current. No smoke was emitted, and the gate charge times were approximately double those of the FGH40N60SMDs I was comparing to, which matches the gate charge increase between the 40N60 and 75N60 parts. Soft switching times were significantly slower on the larger parts, but hard switching was much closer, so everything seems correct.

I have subsequently bought 20 more parts from the same seller, and they seem physically identical to the first lot, and multi-meter test passes as well, though I have not done any other testing. Obviously I cannot tell whether the seller will continue to supply real parts or not, but at under $2 each (less when the seller has a sale) they might be worth the risk!

Hopefully the info about what I bought and the tests I did will be of use to others tempted by cheap deals on Aliexpress/Ebay - I know there are a lot of fakes out there but it seems that I got lucky this time!

Shown in the scan below are a number of the 75N60 parts (included the one I ground down to show the die), along with some 40N60 and 60N65 parts for comparison.

8
Rather a long time ago (2014) I took some interesting measurements of the topload and breakout point current in a medium sized (160mm/6" secondary) DRSSTC at a number of different power levels.

I was always intending to do some post processing on the data to learn more about streamer/arc impedance and topload conditions during a burst, but never ended up having the motivation/time to do so (the idea was to use it as an excuse to learn some python coding skills!). I think it's about time I put this data out in the public for all to have a look at, with the hope that some find it interesting and that it helps us learn more about tesla coil physics.

The other reason to get this out there now is that I'm forgotting some important details about the coil which was measured, as I've been living on the other side of the world from it since these measurements were taken and my notes at the time were limited. I unfortunately can't verify coil parameters or repeat the measurements with more documentation until at least next April. That said, the coil specs I have are as follows:


DRSSTC specs, info:

Secondary: 160mm dia, ~730mm winding length (see attached JavaTC file for more accurate numbers), 1920 turns of 0.315mm dia. wire
Toroid: ~170mm minor diameter, ~760mm major diameter (as above, see attached JavaTC file). Constructed of aluminium ducting.
Primary: 11 turns of 6.35mm dia. copper tube, spaced approx 15mm centre-centre, starting at approx 200mm diameter
Tank capacitor: 48x 2uF 1000V Aerovox snubbers, in 2 parallel strings of 24. Tappable for a range of ~400-166nF at 10-24kV (I believe these tests were at the lower end of this range, likely at 166-200nF)
Coupling: approx 0.15 (adjustable)
IGBTs: 2x CM300DY-24H, ~750A OCD setting
Bus capacitance: 2x4700uF in series
Rectifier: Voltage doubler
Variac: 15A, ~0-260V output
Driver: DIY design based on UD2.5. Can be assumed to be equivalent to any UD2.x design.
Interrrupter: DIY design based on oneTesla midi interrupter code.

The coil is not too sensitive to tuning, and runs happily on both upper and lower pole tuning. I find that with the >600V available with the voltage doubler rectifier that upper pole tuning with higher-Z primary gives nicer, more controllable streamers, especially when playing MIDI music with the coil. I also tried lower pole tuning with a lower impedance primary setup and non-doubler rectifier - this also gave good streamer length but they were more "chaotic", MIDI did not work as well and streamer length was much more sensitive to coil input power.

I've attached a few pictures of the coil in action, with some ground strikes in the ~1.5-2m range. Max strike length achieved is almost 2.5m, or a little over 3x secondary wound length. I have not pushed it properly - the only part I've blown up on this coil was a plugpack supply that was hit by a streamer during the prototype phase!






Video taken while controlling coil - dont drive and film if you want quality!. I believe this was lower pole tuning.

Measurement info:

Scope:
- The topload current measurements were done using a Cleverscope CS328A PC based oscilloscope (see https://cleverscope.com/products/), with the ethernet interface option installed. This allowed me to power the scope and a wifi router off batteries, and locate them on the topload while maintaining control and data download capability remotely from my laptop.
- I've attached a picture of the first rough test setup - the wires were tidied up and the wirewound resistors were replaced for the actual measurements, but the idea remains the same.
- With 5.8GHz wifi, a faraday cage shield could be located over the test equipment, with only a small hole needed to get the wifi signal out, allowing it to be completely safe from the output voltage.
- A small DC offset may be present in the measurements due to non-perfect calibration of the scope - this probably should be removed before doing any calculations using the data.



Probing/measurement setup:
- A 1R resistor was placed in series with the connection from the top of the secondary to the toroid, and the 2R resistor placed in series with the toroid and the breakout point
- All measurements are of the voltages across these resistors, referenced to the toroid. As such, the voltage measured for the breakout current (channel B) is 2V/A and 180 degrees out of phase with the toroid current (channel A), which is 1V/A. Inverting and scaling by x0.5 will correct the channel B voltages and give the breakout point current at 1V/A - channel A data needs no modification and directly shows toroid input current at 1V/A.
- Scope was setup for 30ns between samples (i.e. 33MS/s), with a 20MHz bandwidth filter on both channels. As the input frequency is not expected to be high aliasing shouldn't be present, despite the nyquist sampling criteria not being met. The lowest power measurement was at a slightly slower sampling rate, 50ns between samples (20MSa/s), cant remember why sorry!

Coil operation during measurements:
- The topload currents were measured at 5 different power levels (file naming is related to the descriptions below, should be self-explanatory):
   - Very low power (no breakout)
   - Medium power (breakout into streamer, no ground strike)
   - Higher power (breakout into streamer, no ground strike)
   - Even higher power (small ground strike)
   - Highest power (big ground strike)
- In each case BPS was set to ~100, with power adjusted by changing variac output (and possibly the on-time, unfortunately I can't remember)
- For each power level, the first 100 on-periods from interrupter signal being applied were captured by using the segmented memory of the scope. This allowed for a reasonable sample rate (33MS/s) to be used by only capturing actual data, not the time when the interruptor was off. The number of captures (100 = 1 second at 100BPS) is enough to show the evolution of a streamer or ground strike in a way that a single capture cannot.
- Videos were captured for 3 of the 5 power levels, and can be found here:
I have the original video files if they are useful to anyone, but youtube is more convenient.
- A picture of the coil in it's measurement setup is attached below. The item seen on top of the topload is a plastic block I used to keep the faraday shielding in place.



Notes on captured data:
- All 500 waveform captures are found here, 7zipped up (7zip compressed them much better than plain zipping): https://highvoltageforum.net/files/hydron_topload_current_waveforms.7z
- Each is in a CSV type format (I think the delimiting character is a tab rather than comma), with a few lines of header at the start.
- The "TriggerTime" number is in days from a start-of-1900 epoch (unsure what time zone etc); the fractional part can be converted into seconds by multiplying by 24*60*60. Difference between sequential captures should be very close to 0.010 seconds (100BPS).
- Trigger point will unfortunately not be in exactly the same point every time, as it is triggering off input current which varies depending on power level. Enough pre-trigger data was captured however to show the start of every on-period.


Hopefully this data is of use/interest to some, and can be processed to learn more about the complex impedance of streamers during growth, which may allow for better design decisions to be made when building coils. Some things to remember while doing so:
- This only captures current flowing into the topload capacitance, not the secondary coil capacitance. JavaTC splits these out into separate numbers.
- The breakout point also has it's own additional capacitance to ground. This can be estimated by looking at the low power (i.e. before capacitive streamer forms) measurements of current flowing into it in comparison to the toroid current (which will be the sum of current due to both toroid and breakout capacitance).

Edit: see a couple of waveform captures below, showing raw data before scaling and inversion of channel B

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[General Chat]
davekni
March 26, 2024, 03:19:18 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
March 26, 2024, 01:50:42 AM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 08:05:02 PM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 25, 2024, 07:41:29 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 06:45:46 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 25, 2024, 05:44:25 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
Anders Mikkelsen
March 25, 2024, 04:47:17 PM
post Re: DRSSTC Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alan sailer
March 25, 2024, 04:27:22 PM
post Re-chargeable 1.5 volt lithium ion AAA batteries
[General Chat]
MRMILSTAR
March 25, 2024, 03:57:34 PM
post Re: CM400 Induction Heater
[Electronic Circuits]
markus
March 25, 2024, 02:06:41 PM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 04:43:25 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
davekni
March 25, 2024, 02:39:40 AM
post Re: Odd MOSFET Driver Behavior
[Solid State Tesla Coils (SSTC)]
KrisPringle
March 25, 2024, 12:47:09 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 24, 2024, 07:36:32 PM
post Re: My completed 14-stage Cockroft-Walton voltage multiplier
[Voltage Multipliers]
Alberto
March 24, 2024, 07:27:24 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 24, 2024, 04:25:23 AM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 10:47:35 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 09:30:21 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 04:34:31 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 03:04:25 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 23, 2024, 01:38:34 PM
post Re: capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
MRMILSTAR
March 23, 2024, 04:20:03 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 23, 2024, 12:54:30 AM
post Re: Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
davekni
March 23, 2024, 12:05:57 AM
post capacitor and diodes. Voltage values for a CW
[Voltage Multipliers]
Alberto
March 22, 2024, 11:45:03 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 22, 2024, 11:30:09 PM
post Smoke Screen Machine Protect 950 XP - Teardown of a Smoke Cannon!
[Electronic Circuits]
Mads Barnkob
March 22, 2024, 10:20:35 PM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Benbmw
March 22, 2024, 09:21:13 PM
post Re: What actually kills MOSFETs?
[Beginners]
AstRii
March 22, 2024, 03:37:11 PM
post What actually kills MOSFETs?
[Beginners]
FPS
March 22, 2024, 05:09:20 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 22, 2024, 03:57:54 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 22, 2024, 02:59:25 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 06:31:42 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
rikkitikkitavi
March 21, 2024, 03:08:01 PM
post Re: [WTS] IGBT, Ferrite, Capacitors, Tools, PSU, Industrial components and parts
[Sell / Buy / Trade]
Mads Barnkob
March 21, 2024, 01:37:32 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Alberto
March 21, 2024, 11:42:07 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 21, 2024, 04:09:14 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 21, 2024, 02:15:31 AM
post My Homemade Structural Analysis X-Ray Machine
[X-ray]
Luca c.
March 21, 2024, 01:35:40 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 20, 2024, 10:40:00 PM
post Re: Difference between these transformers
[Transformer (Ferrite Core)]
Mads Barnkob
March 20, 2024, 08:03:41 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Mads Barnkob
March 20, 2024, 07:51:57 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 20, 2024, 10:39:47 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
March 20, 2024, 04:09:59 AM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 20, 2024, 01:13:23 AM
post Re: Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Keybored
March 20, 2024, 12:45:16 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 20, 2024, 12:30:30 AM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 11:12:24 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:47:49 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 19, 2024, 09:44:19 PM
post Phase Lead Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Saattvik24
March 19, 2024, 06:52:09 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
March 19, 2024, 05:02:44 PM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
Mads Barnkob
March 19, 2024, 05:01:41 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 04:31:02 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
March 19, 2024, 03:59:54 PM
post Re: Benjamin's DRSSTC 2 in progress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Benjamin Lockhart
March 19, 2024, 06:41:39 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
davekni
March 19, 2024, 04:05:49 AM
post Re: Welcome new members, come say hello and tell a little about yourself :)
[General Chat]
OmGigaTron
March 18, 2024, 09:08:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 09:07:35 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
Twospoons
March 18, 2024, 08:57:06 PM
post Re: Can I Trust This Super Cheap Site?
[General Chat]
MRMILSTAR
March 18, 2024, 03:51:33 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:59:46 PM
post Re: 160mm DRSSTC II project | Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Late
March 18, 2024, 02:33:25 PM
post Can I Trust This Super Cheap Site?
[General Chat]
2020-Man
March 18, 2024, 11:02:12 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
Twospoons
March 18, 2024, 02:36:11 AM
post Re: Best forum for vacuum tube amplifiers?
[General Chat]
Mads Barnkob
March 17, 2024, 07:42:55 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 04:15:14 PM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Michelle_
March 17, 2024, 05:05:04 AM
post Re: Where's all this voltage coming from?
[Spark Gap Tesla Coils (SGTC)]
davekni
March 17, 2024, 04:50:51 AM
post Re: 2x Panasonic Inverter Microwaves - what to salvage, dangers?
[General Chat]
Twospoons
March 17, 2024, 04:45:17 AM

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